China invented something that could replace jet engines

A Chinese team recently demonstrated the prototype of a microwave plasma propulsion in laboratory conditions.

Previously, plasma propulsion was used on spacecraft, using xenon plasma. But this type of engine cannot be used in the Earth's atmosphere, because the accelerated xenon ions lose most of the thrust to friction with the air.

However, a research team from the Institute of Science and Technology at Wuhan University, China, has found a new design that makes the engine use only air and electricity. This device works by ionizing the air to create a low temperature plasma, which is then blown through a tube with an air compressor. In the tube, the plasma is attacked by very powerful microwaves, which vibrate violently with ions, causing them to smash into other non-ionized atoms and significantly increase the temperature and pressure of the plasma. This temperature and pressure creates significant thrust on the pipe.

Microwave plasma propulsion design.

Created by an electromagnet of 1 kW, 2.45GHz, the microwaves were compressed in a flattened waveguide before reaching the plasma stream. This enhances the electric field and transmits as much heat and pressure to the plasma as possible.

The researchers found that, while keeping the air stream from the compressor stable, sparks in the tube seemed to last longer as the microwave's output increased. They aim to try to measure how much thrust is generated, but this is not easy using conventional methods.

Instead, they decided to balance an empty steel ball on top of the pipe, which could easily change weight. At a certain weight, the repulsion will resist gravity pulling the ball down and starting to lift it out of the tube, causing it to move and jump continuously. The researchers then made the measurements of the repulsion generated.

Steel spheres are used to measure thrust.

After testing through a series of power levels and compressed air flow rates, the researchers found a linear relationship between thrust and both microwave and airflow. Efficiently, the thrust at 400W and 1.45 cubic meters of air per hour is 11 Newtons, the equivalent of converting power into thrust at 28N / kW. Thereby, the team speculated that if using the Tesla battery of the Model S model, capable of producing 310 horsepower, the thrust generated would be about 8,500 N.

This allows it to be used as an engine for future electric aircraft. In fact, the Airbus E-Fan electric aircraft uses a pair of engines with 25 N / kW efficiency, lower than the first prototype assembled in a laboratory in Wuhan. Therefore, the researchers concluded that this thrust was "equivalent to the jet engine of commercial aircraft".

However, the method of testing with steel balls is not really reliable and needs to improve the efficiency of the design. But everything seems to be promising, with the idea of ​​creating a new type of plasma propulsion for future electric aircraft.

Even so, the distance to reality is still extremely remote. Because even though it is more efficient than conventional jet engines, it is undeniable that, if taken at the same weight, aviation fuel still carries dozens of times more energy than a lump. the battery.

 Video of microwave plasma propulsion test by Chinese researchers.